Bis(chloromethyl)dichlorosilane (BCMCS) and bis(chloromethyl)(aryl)chlorosilane (BCMACS) are versatile starting materials in synthetic organosilicon chemistry with broad applications in advanced silicon materials and pharmaceuticals. They are also key building blocks for preparation of advanced silicon-containing catalysts for olefin polymerizations. Unfortunately, there has been no practical method to prepare these important materials. The currently known preparation methods for BCMCS include the following methods shown below:

The currently known preparation methods for BCMACS, wherein the aryl group is phenyl, include the following method shown below:

The currently known preparation methods for BCMCS or BCMACS either require dangerous chemistry (diazomethane), or utilize expensive strong acids while generating highly toxic byproducts (benzene, in the case of Ar=phenyl), and low yields.
Accordingly, there is a need for an improved and practical method for preparation of bis(chloromethyl)dichlorosilane and bis(chloromethyl)(aryl)chlorosilane in high yield safely at a relatively low cost.